Lesbianism in erotica deals with depictions in the visual arts of lesbianism, which is the expression of female-to-female sexuality. His most famous model was Bettie Page, who became the first celebrity of bondage film and photography. Patricia Hill Collins, an African-American writer, theorizes that this is derived from a stereotype that those of black descent are promiscuous, and their buttocks are objectified by porn as a result. The study also found that participants reacted positively hentai movies to a much wider range of figures than a control group, even rating emaciated figures higher. The loose and direct camera work often includes tight shots of the genitalia, unlike some traditional porn. Group sex also occurs in populations of non-human animals such as bonobo apes and chimpanzees. Standing up, a chair, the corner of an item of furniture, or even a washing machine can be used to stimulate the clitoris through the labia and clothing. Sadomasochistic scenes sometimes reach a level that appear more extreme or cruel than other forms of BDSM—for example, when a masochist is brought to tears or is severely bruised—and is occasionally unwelcome at BDSM events or parties. Reading or viewing pornography, gay movies sexual fantasy or other erotic stimuli may lead to a desire for sexual release such as by masturbation. Some people get sexual pleasure by inserting objects, such as urethral sounds, into the urethra lesbian milfs , a practice known as urethral play or sounding. Some celebrity porn
masturbate only using pressure applied to the clitoris without direct contact, for example by pressing the palm or ball of the hand against underwear or other clothing. By comparison, gonzo pornography puts the camera right into the action, often with one or more of the participants both filming and performing sexual acts, without the usual separation between camera and performers seen in conventional porn and cinema. In Japanese, the term describes any type of perverse or bizarre sexual desire or act; it does not represent a genre of work.